code: def test_get():
      response = client.post(
          "/invoices/",
          json={"id": "fooinvoice", "customer": "John", "total": 5.3},
      )
      assert response.status_code == 200, response.text
      assert response.json() == {"msg": "Invoice received"}
  
file_path: fastapi/tests/test_sub_callbacks.py
imports: from typing import Optional
  from dirty_equals import IsDict
  from fastapi import APIRouter, FastAPI
  from fastapi.testclient import TestClient
  from pydantic import BaseModel, HttpUrl
label_desc: Use image node_id 4 for calling a global function with example usage: test_get() without return types